1. Field of Invention
This invention is related to thermosetting liquid coating compositions and particularly to compositions containing blocked acid catalysts prepared from oxirane-containing materials and sulfonic acids.
2. Description of Prior Art
Coating compositions containing polymers which are capable of being crosslinked, crosslinking agents, and various catalysts facilitating the crosslinking step are well known. The prior art is replete with compositions which contain strong acid catalysts such as para-toluene-sulfonic acid and there also appear references to blocked catalysts.
U.S. Pat. No. 3,868,338, issued Feb. 25, 1975 to T. E. Parsons, et al., discloses thermosetting powder coating compositions based on polyester, cellulose acetate butyrate, crosslinking agent, and a blocked catalyst. Such compositions, however, are not commonly useful as liquid coating compostions.
U.S. Pat. No. 3,846,368, issued Nov. 5, 1974 to P. H. Pettit, Jr., discloses thermosetting powder coating compositions based on soft acrylic polymer, hard acrylic polymer, alkylated melamine formaldehyde resin, dihydroxy-functional plasticizer, and blocked acid catalyst. Such compositions, however, are also not commonly useful as liquid coating compositions.